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Layer Removal (layer + removal)
Kinds of Layer Removal Selected AbstractsThe smear layer in endodontics , a reviewINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2010D. R. Violich Abstract Root canal instrumentation produces a layer of organic and inorganic material called the smear layer that may also contain bacteria and their by-products. It can prevent the penetration of intracanal medicaments into dentinal tubules and influence the adaptation of filling materials to canal walls. This article provides an overview of the smear layer, focusing on its relevance to endodontics. The PubMed database was used initially; the reference list for smear layer featured 1277 articles, and for both smear layer dentine and smear layer root canal revealed 1455 publications. Smear layer endodontics disclosed 408 papers. A forward search was undertaken on selected articles and using some author names. Potentially relevant material was also sought in contemporary endodontic texts, whilst older books revealed historic information and primary research not found electronically, such that this paper does not represent a ,classical' review. Data obtained suggests that smear layer removal should enhance canal disinfection. Current methods of smear removal include chemical, ultrasonic and laser techniques , none of which are totally effective throughout the length of all canals or are universally accepted. If smear is to be removed, the method of choice seems to be the alternate use of ethylenediaminetetraacetic acid and sodium hypochlorite solutions. Conflict remains regarding the removal of the smear layer before filling root canals, with investigations required to determine the role of the smear layer in the outcomes of root canal treatment. [source] The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysisINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2005C. S. Teixeira Abstract Aim, To verify, under the scanning electron microscope (SEM), the influence of irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on intracanal smear layer removal. Methodology, Twenty-one extracted human permanent teeth with single straight root canals were included. The root canals of the teeth were instrumented and, at the end of preparation, were irrigated with 3 mL of 15% EDTA, followed by 3 mL of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min (group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of cervical, middle and apical thirds was graded according to the amount of debris and smear layer remaining on the walls. The results were analysed using the Kruskal,Wallis and Conover,Inman tests. Results, In all the canals of experimental groups irrigation with EDTA and NaOCl completely removed the smear layer from the cervical and middle thirds. In the apical third, the dentine surface were partially covered, particularly in the teeth of group 1, where there was significantly more smear layer when compared with the other thirds in the same group (P < 0.007). However, the Kruskal,Wallis test showed overall that there were no significant differences between groups 1, 2 and 3 (P > 0.05). Conclusion, In this limited laboratory study, canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were equally effective in removing the smear layer from the canal walls of straight roots. [source] Light and scanning electron microscopic evaluation of GlydeÔ File Prep in smear layer removalINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2003T. S. Lim Abstract Aim, To evaluate the effectiveness of GlydeÔ File Prep used in conjunction with sodium hypochlorite irrigation in the removal of smear layer produced during root canal instrumentation. Methodology, Thirty-nine extracted human teeth with single root canals were used. Access cavities were prepared and the teeth divided into three groups of 13 teeth each. Each group was treated by one of the three different regimes of irrigation and conditioning during root canal instrumentation. Group A: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 1% NaOCl; group B: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 17% EDTA; group C: GlydeÔ File Prep coated on each instrumentation file used in conjunction with 0.5 mL 1% NaOCl irrigation after each file size and an additional final irrigation of 10 mL 1% NaOCl. The teeth were then longitudinally grooved and sectioned. Root canal cleanliness was evaluated with the aid of a Nikon light microscope (×40 and ×100) and scanning electron microscope (×1000 and ×3000). The debris scores obtained at three canal regions were compared statistically within the same group and among different groups using repeated measurements of analysis of variance (anova) with Bonferroni adjustments and anova with posthoc Tukey HSD, respectively. Results, The canals treated with EDTA and GlydeÔ File Prep were significantly cleaner than those treated with NaOCl alone. The apical region of the root canals generally displayed more residual smear layer, but the difference was not significant. Conclusions, Used in conjunction with NaOCl irrigation, GlydeÔ File Prep was effective in removing smear layer produced during root canal instrumentation. [source] Evaluation of smear layer removal by EDTAC and sodium hypochlorite with ultrasonic agitationINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2002D. M. Z. Guerisoli Abstract Aim To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation. Methodology Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of smear layer by three independent and calibrated examiners. The scoring system ranged from 1 (no smear layer) to 4 (all areas covered by smear layer). Due to the non-parametric nature of the data, Friedman's test was used for statistical analysis. Results Canal walls were covered with smear layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less smear layer throughout the canal (P < 0.001). There were no statistical differences for the amount of smear layer found on the cervical, middle and apical thirds when each group was analysed separately. Conclusions Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer. [source] A disc brake test stand for measurement of airborne wear particlesLUBRICATION SCIENCE, Issue 6 2009Jens Wahlström Abstract During braking, there is wear on both the rotor and the pads. This process generates particles that may become airborne. In field tests, it is difficult to distinguish these particles from others in the surrounding environment. Therefore, a laboratory test stand has been designed which allows control of the cleanliness of the surrounding air. The test stand consists of a front right brake assembly mounted in a sealed chamber. A braking load is applied by a pneumatic system and the rotor, which has been pre-conditioned with a rust layer to simulate a car standing parked overnight in a wet environment, is driven by an electric motor. The number and size of airborne wear particles are then measured. This experimental set-up has been verified by an initial test series performed at low braking loads. The results suggest that this test stand can be used to study rust layer removal from the rotor. Copyright © 2009 John Wiley & Sons, Ltd. [source] Evaluation of the smear layer and hybrid layer in noncarious and carious dentin prepared by air abrasion system and diamond tipsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2010Ana Carolina Mascarenhas Oliveira Abstract Purpose: To analyze the smear layer and the hybrid layer in noncarious and carious dentin prepared by different cutting instruments and restored with composite resin. Study design: Cavities were randomly prepared in 160 specimens (noncarious and artificial carious dentin) by high-speed diamond tips (KG Sorensen 1013), air abrasion system (Prepstart, Danville Engineering), ultrasonic tip (CVDentus 8.3231-1), and ultrasonic tip associated with ultrasonic cavitation by water for 10 s. Half of the cavities in each group were conditioned with 37% phosphoric acid for 15 s. The amount of smear layer and dentinal tubules present were analyzed using scanning electron microscopy and graded from 0 to 3. Cavities were prepared in another 20 noncarious specimens and 20 carious specimens and restored with adhesive composite resin system. The restorations were hemisected longitudinally and analyzed using scanning electron microscopy to evaluate the hybrid layer and resinous prolongation characteristics, using scores ranging from 1 to 6. Results: The data were statistically analyzed using Kruskal-Wallis and Dunn tests at 5% of significance level. There was evidence that the most efficient smear layer removal was the acid etching in the noncarious dentin and the water ultrasonic cavitation in the carious dentin. The hybrid layer formed on the noncarious and carious dentin prepared by the ultrasonic tip was more regular than in the specimens prepared by high-speed diamond tip, with many resinous prolongations. Conclusion: The ultrasonic tip seems to be a promising tool for carious dentin cavity preparation. Microsc. Res. Tech., 2010. © 2009 Wiley-Liss, Inc. [source] Effect of 17% EDTA and MTAD on intracanal smear layer removal: A scanning electron microscopic studyAUSTRALIAN ENDODONTIC JOURNAL, Issue 1 2009Mohammad Ali Mozayeni dds Abstract The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty-five extracted maxillary and mandibular single-rooted human teeth were prepared by a crown-down technique using rotary 0.04 and 0.06 taper nickel-titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals. [source] Controlled enzymatic removal of damaging casein layers on medieval wall paintingsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2002Sascha Beutel Abstract A new, gentle enzymatic method was developed for a controlled removal of casein layers from medieval wall paintings. These casein layers were applied over the last 60 years on wall paintings in order to decrease substantial damage due to a peeling off of the frescoes from the roughcast surface due to environmental effects. However, due to the aging of the casein layers (at 40,50 years), a more drastic peeling occurred and the danger of total destruction of the wall paintings is severe. Thus, screening was performed to find the most suitable enzyme for casein digestion. Alcalase 2.5 DX L was the most appropriate enzyme for an effective proteolysis reaction. The enzyme was immobilized on functionalized cellulose membrane. A membrane pad system with immobilized enzymes was developed which could be pressed on the casein layers on the wall painting. A controlled removal of the casein layers by proteolytic digestion was observed and it was possible to continuously wash off the hydrolyzed casein fragments from the wall painting surface by an aqueous carbonate buffer flowing through the membrane pad. The removal and the digestion was monitored by reverse HPLC. Additionally, an on-line monitoring system was set up in order to continuously follow the casein layer removal and the digestion procedure directly on the wall painting. This technique is based on noninvasive 2D-fluorescence monitoring. Optical fiber systems were used to continuously monitor the fluorescence intensity of casein-bound tryptophan. The off-line data were verified with the on-line 2D-fluorescence data. Based on the scientific result an appropriate technique for the controlled enzymatic removal of damaging casein layers on the surface of medieval wall paintings using immobilized enzyme is now available. It is now applied to remove such casein layers from medieval wall paintings in the Allerheiligen-Kapelle Cloister, Wienhausen, Germany, and the St. Alexander Kirche, Wildeshausen, Germany. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 13,21, 2002. [source] | ||||||||||